/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * COPYING NOTES
 *
 * timeout.c -- a timeout handler for shell commands
 *
 * Copyright (C) 2005-6, Roberto A. Foglietta <me@roberto.foglietta.name>
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; version 2 of the License.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
 */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * REVISION NOTES:
 * released 17-11-2005 by Roberto A. Foglietta
 * talarm   04-12-2005 by Roberto A. Foglietta
 * modified 05-12-2005 by Roberto A. Foglietta
 * sizerdct 06-12-2005 by Roberto A. Foglietta
 * splitszf 12-05-2006 by Roberto A. Foglietta
 * rewrite  14-11-2008 vda
 */
//config:config TIMEOUT
//config:	bool "timeout (6.5 kb)"
//config:	default y
//config:	help
//config:	Runs a program and watches it. If it does not terminate in
//config:	specified number of seconds, it is sent a signal.

//applet:IF_TIMEOUT(APPLET(timeout, BB_DIR_USR_BIN, BB_SUID_DROP))

//kbuild:lib-$(CONFIG_TIMEOUT) += timeout.o

//usage:#define timeout_trivial_usage
//usage:       "[-s SIG] [-k KILL_SECS] SECS PROG ARGS"
//usage:#define timeout_full_usage "\n\n"
//usage:       "Run PROG. Send SIG to it if it is not gone in SECS seconds.\n"
//usage:       "Default SIG: TERM."
//usage:       IF_PLATFORM_MINGW32("\n")
//usage:       "If it still exists in KILL_SECS seconds, send KILL.\n"

#include "libbb.h"

#if ENABLE_PLATFORM_MINGW32
static HANDLE child = INVALID_HANDLE_VALUE;

static void kill_child(void)
{
	if (child != INVALID_HANDLE_VALUE) {
		pid_t pid = (pid_t)GetProcessId(child);
		if (pid)
			kill(pid, SIGTERM);
	}
}

/* Return TRUE if child exits before timeout expires */
static NOINLINE int timeout_wait(duration_t timeout, HANDLE proc, DWORD *status)
{
	DWORD t = (DWORD)(timeout * 1000);
	if (WaitForSingleObject(proc, t) == WAIT_OBJECT_0) {
		/* process is gone */
		GetExitCodeProcess(proc, status);
		return TRUE;
	}
	return FALSE;
}
#else
static NOINLINE int timeout_wait(duration_t timeout, pid_t pid)
{
	/* Just sleep(HUGE_NUM); kill(parent) may kill wrong process! */
	while (1) {
#if ENABLE_FLOAT_DURATION
		if (timeout < 1)
			sleep_for_duration(timeout);
		else
#endif
			sleep1();
		if (--timeout <= 0)
			break;
		if (kill(pid, 0)) {
			/* process is gone */
			return EXIT_SUCCESS;
		}
	}
	return EXIT_FAILURE;
}
#endif

int timeout_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int timeout_main(int argc UNUSED_PARAM, char **argv)
{
	int signo;
#if !ENABLE_PLATFORM_MINGW32
	int status;
	int parent = 0;
#else
	intptr_t ret;
	DWORD status = EXIT_SUCCESS;
#endif
	duration_t timeout;
	duration_t kill_timeout;
	pid_t pid;
#if !BB_MMU
	char *sv1, *sv2;
#endif
	const char *opt_s = "TERM";
	char *opt_k = NULL;

#if ENABLE_PLATFORM_MINGW32
	xfunc_error_retval = 125;
#endif

	/* -p option is not documented, it is needed to support NOMMU. */

	/* -t SECONDS; -p PARENT_PID */
	/* '+': stop at first non-option */
#if !ENABLE_PLATFORM_MINGW32
	getopt32(argv, "+s:k:" USE_FOR_NOMMU("p:+"), &opt_s, &opt_k, &parent);
#else
	getopt32(argv, "+s:k:", &opt_s, &opt_k);
#endif
	/*argv += optind; - no, wait for bb_daemonize_or_rexec! */

	signo = get_signum(opt_s);
#if !ENABLE_PLATFORM_MINGW32
	if (signo < 0)
#else
	if (!is_valid_signal(signo))
#endif
		bb_error_msg_and_die("unknown signal '%s'", opt_s);

	kill_timeout = 0;
	if (opt_k)
		kill_timeout = parse_duration_str(opt_k);

	if (!argv[optind])
		bb_show_usage();
	timeout = parse_duration_str(argv[optind++]);
	if (!argv[optind]) /* no PROG? */
		bb_show_usage();

#if !ENABLE_PLATFORM_MINGW32
	/* We want to create a grandchild which will watch
	 * and kill the grandparent. Other methods:
	 * making parent watch child disrupts parent<->child link
	 * (example: "tcpsvd 0.0.0.0 1234 timeout service_prog" -
	 * it's better if service_prog is a child of tcpsvd!),
	 * making child watch parent results in programs having
	 * unexpected children.	*/

	if (parent) /* we were re-execed, already grandchild */
		goto grandchild;

#if !BB_MMU
	sv1 = argv[optind];
	sv2 = argv[optind + 1];
#endif
	pid = xvfork();
	if (pid == 0) {
		/* Child: spawn grandchild and exit */
		parent = getppid();
#if !BB_MMU
		argv[optind] = xasprintf("-p%u", parent);
		argv[optind + 1] = NULL;
#endif
		/* NB: exits with nonzero on error: */
		bb_daemonize_or_rexec(0, argv);
		/* Here we are grandchild. Sleep, then kill grandparent */
 grandchild:
		if (timeout_wait(timeout, parent) == EXIT_SUCCESS)
			return EXIT_SUCCESS;
		kill(parent, signo);

		if (kill_timeout > 0) {
			if (timeout_wait(kill_timeout, parent) == EXIT_SUCCESS)
				return EXIT_SUCCESS;
			kill(parent, SIGKILL);
		}

		return EXIT_SUCCESS;
	}

	/* Parent */
	wait(&status); /* wait for child to die */
	/* Did intermediate [v]fork or exec fail? */
	if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
		return EXIT_FAILURE;
	/* Ok, exec a program as requested */
	argv += optind;
#if !BB_MMU
	argv[0] = sv1;
	argv[1] = sv2;
#endif
	BB_EXECVP_or_die(argv);
#else /* ENABLE_PLATFORM_MINGW32 */
	argv += optind;
	if ((ret=mingw_spawn_proc((const char **)argv)) == -1) {
		xfunc_error_retval = errno == EACCES ? 126 : 127;
		bb_perror_msg_and_die("can't execute '%s'", argv[0]);
	}

	child = (HANDLE)ret;
	atexit(kill_child);
	if (timeout_wait(timeout, child, &status))
		goto finish;
	status = signo == SIGKILL ? 137 : 124;

	pid = (pid_t)GetProcessId(child);
	if (pid) {
		kill(pid, signo);

		if (kill_timeout > 0) {
			if (timeout_wait(kill_timeout, child, &status))
				goto finish;
			kill(pid, SIGKILL);
			status = 137;
		}
	}
 finish:
	CloseHandle(child);
	child = INVALID_HANDLE_VALUE;
	return status;
#endif
}
